137440-44-9Relevant academic research and scientific papers
Ring-size ans Substituent Effects in Intramolecular Reactions of Alkylidenecarbenes (Carbenoids)
Baird, Mark S.,Baxter, Anthony G. W.,Hoorfar, Alireza,Jefferies, Ian
, p. 2575 - 2582 (2007/10/02)
Intramolecular reaction of methylenecarbenes (carbenoids), derived by reaction of 1,1-dibromoalkenes and methyllithium, with 5,6-related C-H bonds leads to cyclopentenes when there is an alkoxy or amino substituent on C-5, but no reaction occurs at a 4,5-related C-H bond when there is a heteroatom on C-4; when there is an alkylthio group either on C-4 or C-5 attack occurs on sulphur and the alkyl group is lost, leading to a 2,3-dihydrothiophene or a 3,4-dihydro-2H-thiopyran respectively.If a heteroatom-hydrogen bond is present at the 5,6-position a formal insertion occurs at that bond leading to 2,3-dihydropyrroles, 2,3-dihydrofuranes or 2,3-dihydrothiophenes.
